Linux Kernel Out-of-Bounds Read Vulnerability in DRM/DP Handling

A vulnerability in the Linux kernel's Direct Rendering Manager (DRM) and DisplayPort (DP) handling has been addressed. The issue was an out-of-bounds (OOB) read caused by the link_status array being too small to properly read the Adjust Request Post Cursor2 register. This flaw was identified with a compiler warning about array bounds. The vulnerability arose in the 'drm_dp_get_adjust_request_post_cursor' function within the 'drm_dp_helper.c' file, where an array subscript accessed data outside the array's defined limits. The vulnerability has been fixed by replacing the common helper function with an open-coded fetch and decode, similar to existing practices in the AMD display driver.

Impact

Exploitation of this vulnerability could lead to out-of-bounds read, potentially allowing for information disclosure or memory corruption.